flanders



Dec. 17, 1929- R. E. FLANDERS GRINDING MACHINE Original Filed May 27.

.1922 13 Sheets-Sheet l Dec. 17,' 19.29..` R. E. FLANDERS GRINDING MACHINE Original Filed My' 27, 1922 13 Sheets-Sheet 2 Z' IW?? K??? d Dem 17, H929- R. E. FLANDERS GRINDING MACHINE Original Filed May 27. 1922 13 Sheets-Sheet 5 Original Filed May 27. 1922 13 Sheets-Shea?I 4 Dec. 17, 1929. R. E. FLANDERS GRINDING MACHIN 13 sheets-sheet 6 Original Filed May 27. 1922 Dec 17, 1929. R. E. FLANDERS y GRINDING MACHINE Original Filed May 27. 1922 l5 Sheets-Sheet 7 Z/mmr /7 Z% @M7 www De@`- 17, 1929- R. E. FLANDERS 1,739.753

GR'INDING MACHINE original Filed May 27. 1922 15 sheets-sheet 8 Dec. 17, i929. R. E. FLANDERS GRINDING MACHINE 13 Sheets-Sheet 9 Original Filed May 27. 1922 GRINDING MACHINE Original Filed May 27. 1922 13 Sheets-Sheet 10 s @I A IU Y y W@ i 11 Dec. 17, 1929.

RE. FLANDERS GRINDING MACHINE 13 Sheets-Sheet 11 Original Filed May 27. 1922 Dec. 17, 1929. R. E. FLANDERS 1,739,753

GRINDING MACHINE Original Filed May 27. 1922 lli/Mms' 1s sheets-snaai 12 V Dec; 17, 1929. R. E. FLANDERS 1,739,753

GBINDING MACHINE:

Original Filed May 27. i922 13 Sheets-Sheet 21.3V

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Patented Dec. 17, 1929 UNITED 4STATES PATENT OFFICE -RALPH E. FLANDERS, OF SPRINGFIELD, VERTV'IONT, ASSIGNOR TO'JONES & LAMSON MA- CHINE COMPANY, OF SPRINGFIELD, VERMONT, A CORPORATION 0F VERMONT GRINDING Application filed May 27, 1922, Serial N0. 564,091.

This invention relates to grinding ma chines, having been particularly designed for grinding the threaded faces of taps. Taps are iiuted longitudinally to form cutting edges with the si( es of the threads and in order to cut properly it is desirable to form the threaded portions of less diameter back from the cutting edges at the flutes in order to give clearance for these cutting edges. For this purpose this invention provides means for automatically increasing and decreasing the depth of cut on the threaded faces in proper relation to the flutes to provide a proper backing off or clearance for the cutting edges of the tap.

Another feature of this invention relates to the truing devices for insuring that the grinding is effected to the desired contour.

A further feature of the invention relates to mechanism by which correct sii/,ing` of the taps is insured automatically regardless of the amount of truing` imparted to the grinding wheel during the grinding on'each tap or in operating on successive taps, and means by which the amount of truinf' each instance may be adjustably detern'iined.

Further objects and advantageous details and combinations of parts will appear from a more complete description of one embodiment of the invention shown in ti c accomn panying drawings in which Figure l is a front elevation of the machine.

Figure 2 is a left side elevation.

Figure 3 is a right side elevation. Figure MACHINE Renewed March 6, 1929.

Figure il is a fragmentary section similar to a portion of Figure 5, but drawn to a larver scale.

Figure l2 is a fragmentary right-hand ele vation similar te a portion of Figure 3, but drawn to larger scale.

Figure `i3 is a fragmentary view partly in section of a modified form of truing mechanism.

Figure lil is a section on the line 14-14 of Fiure 13.

Figure l5 is a fragmentary section illustrating a modified form of tap-relieving mechanism.

Figure 16 is a sectional detail through a lrnoclzsoitf mechanism.

This machine in general comprises means for supporting a tap between centers and rotating the tap, means for supporting and driving a grinding wheel in operative relation to the tap, means for effecting a trav erse longitudinally of the tap between the wheel and the tap, means for effecting a relative movement between the tap and the wheel to back olf or relieve the tap from its cutting edges, wheel-truing devices, and means for actuating the truing devices in such manner that the contour of the wheel is maintained correct and so that the tap may be ground to correct finished size.

life/re supporting ma? actuating mechanism ln the machine shown a base l is employed t rt the various mechanisms and for i .pose of supporting the work-holding centers may be provided on its upper forward face with a pair of guides 2 for slidably supporting a traversing carriage 3. Thilo as shown the traversing carriage slides, it might be otherwise supported with capability of traversing movement in any suitable way. Depending from the carriage 3 between the guides 2 sh( vn a bracket e (see Figure 5) having journaled therein at its lower end a cai-n follower roll 5 bearing against an edge cam 6. This edge cam is carried by a drum 7 journaled on a vertical stub shaft 8 fixed in the machine base. The edge cam 6 acting on the roll 5 causes traversing movements of the carriage in one direction, while the return center 30.

movement is eii'eeted by means of a tension spring l0 fixed at its outer end to a bracket 1l dejiending from the carriage7 passing through an opening l2 in the base l, and made Yfast inside this base to a pin 13 fixed in position thereon. This spring serves to urge the cam follower 5 against the cam 6. The traversing motion ot the carriage may be limited in one direction by means of an adjusting screw 14 threaded through the bracket l1 and impinging on a portion oi thev base l.

The carriage 3 carries the head and tail stocks for supporting the tap. is shown the head stock comprises a sleeve 2O adjustable longitudinally within a bearing 2l projecting upwardly from one end ot the car riage. This adjustment may be elected by means of a toothed stud Q2 journaled in the bearing 2l, the teeth ot which mesh with .rack tee 2h. 23 formed in the sleeve 20. Forwardly otithe bearing 2l this stud Q2 may be provided with a head 24 by which it may be turned to adjust the sleeve and suitable clan-iping bolts 25 may be employed to tix the sleeve 2O in adjusted position, this method ot adjusting and clamping being well known in the art.

Slidable within the sleeve Q() is a center 30. This center may be supported in any suitalile way, one method well known in the art being shown in which the center has slidable in a socket in its rear end a pin 8l urged outwardly therelrom by means of a spring 232. This pin impinges on the inner tace ot a cap 33 made last by threaded or other suitable connections tothe outer end ci" the sleeve 20. By this means the center 30 is urged away from the cap 33 as 'liar as is permitted by the engagement oli rack teeth thereon with a segment 35 lixed to a vertical shalt 3G which has an operating handle 37 at its upper end above the cap 33. This spring 32 prevents lost motion between the rack and segment.

The inner end ot the sleeve 520 may carry a tace plate Ll() having iixed thereto an outwardly extending arm ll-l for engagement with a dog or other suitable device7 as shown in Figure 8 clamped to the cap T placed between thecentcrs. This tace plate is rotated, this being eiilected, as shown, by n'ieans of a gear portion 4t2 'formed on the tace plate with which meshes a pinion fixed to a shaft all journaled in parallel relation to the This shalt 44 is journaled in a sleeve l5 fixed to move with the sleeve 20 and slidable through a portion ci bearing 2l and is also journaled in a sleeve i6 also slidable through one wall ot the bearing 2l. Betweenthe sleeves Zl5 and l-ti shaft lli-l has fixed thereon a gear t7 which meshes with a long gear 48 keyed to a sha'lit 49 which extends the length ot the carriage 3. The gear 4S is of sutlicient length to permit the mesh-- ing oit the gear 47 therewith throughout the ,V a similar manner to the stud 22.

may be turned by means ot a bolt head 64 (see range ot axial movement ot the sleeve 20. The shaft 4:9 has fixed thereon a long gear 50 by which it may be rotated in a manner to be later described.

The tailstock, positioned opposite the headstock in the usual manner, comprises a sleeve (SO similar to the sleeve 20 and slidable axially through a bearing G1 in which it is adjustable by means of a toothed stud 62 constructed in The stud 62 Figure l) and may be fixed in adjusted position by clamping bolts 65 in the same manner as the sleeve 2O of the headstock. The sleeve (30 has passing therethrough a center 7 (l. The inner end of this center terminates in the usual cone point 7l and back ot this point it has iixed thereto a bearing block 72 having a spherical shaped bearing lace seated within a mating socket plate 73 bolted through mating flanges 7 el: and 75 to the inner end of the sleeve 60, the tiange 75 being preterably formed integ 1al with this sleeve. This mounting ot the inner end of the tailstock center permits a universal pivotal or gyratory motion of this center and forms one construction for effecting the relieving action i'or the cutting edges of the tap, as will he described.

The rear end of the center is ot reduced diameter and passes through a central opening in a sleeve 7 5 journaled within the outer end of the sleeve 60. The outer end of this sleeve has lixed or integral therewith. a gear 77 which bears closely against the outer end of the sleeve 60. This portion of the mechanism is shown to an enlarged scale in Figure ll. Adjacent this gear 77 the sleeve 60 is shown of reduced diameter and carries positioned thereon a depending bracket arm 78 which is employed to carry certain of the driving mechanism Afor ctllecting the gyratory motion of the center in a manner which will be described. This bracket 7S is lixed against a shoulder 79 formed by the reduced portion of the sleeve 60, by means of a collar 80 threaded over the outer threaded end of this sleeve GO and bearing hard against the bracket. The gear 77 is recessed on its outer face to form a pair of parallel guideways 85 in which is movable a slide 8G, this slide being adjustable across the axis of the gear 77 (Fig ures 1l and l2). This slide has a central circular opening 87 therein and within this opening is positioned a collar 88 having its outer edge formed spherical, this collar being fixed to the center 70. By adjusting the slide 86 so as to position the opening 87 out oi; the axis of the gear 77 rotation imparted to the gear 77 causes a circular bodily movement to be imparted to the collar S8 to effect a gyratory motion of the center 7 O, this center not revolving about its own axis. The position ot the sli de 8G may be fixed by means of tightening screws 89 passing through slots 89 therein and in order to show the adjust" ment effected a scale may be marked on one oif the guideefays cooperatiniwith an index rnarir on the slide to indicate the ainount by which the collar 88 is moved oit center with relat in to the axis er the rear Ti". core A1,. 1 1 pia-te Q0 is p lsitioned against the outer tace oiE the slide 86 to carry the screws S9 and against this cover plate bears a Washer 91 wl eh is urged inwardly against the cover plate neans ot a spring 92 surrounding` the reduced portion 93 oi a lrnurled adjustine' lrnob 9'4- threaded on the outer end Oi the center TO.

The gjiratory motion of the cone point 71 inuch smaller amplitude than that will be o f ot the collar 8S, due to the lengths oit the lever arnis ot these tif-fo elements ifi-oui the center ot niotion @eterniined by he bloclr 72 and its socket plate 73, This irotion, l'nieveyeru is iniiizaitee te tl e end ot the tap, the shank end et which is -eiably te i ,d by the ireehenisn. Tn the present einl odiinent this gearingry con prises a sieeve 1.00 journaled in the lraclret 78 and slidabiy keyed te the reduced entren'iity 101 ot l Lhis l t; f ns et a tl i er103which r1(`--c shaft i c i n an arcuate slot 1 6 in the ig as its center the axis oi the :haft 1 also carries a gear es with the gear 77. By se- 03 of thl proper size the corrotations ot 'the gear 77 to f proper number et gyratory inov'enients t the center 70 in tiine with the rotation of the and pr perly related to et the tap inay be effected.

inethcr et effecting a suitable rethe `fletes li .j rnoren'ient to the center is illustrated ii `ture 15 in which, instead producing` nent to the center. a pivotal a v inevei n imparted tl'ierete about an axis ular to that plane which passes ti' lhe et the tap and the central pactiou therewith of the grinding r' te ig to this Figure the inner (nc sii-ere has lined thereto a cap or head 110 "i which passes a pivot 11 lornnng alo whirl the center TO is pirated. ie pire 111 is Vertical in the present embodiment since the grinding Wheel acts on one side ot the Work in a hori- Zontal plane Coi'itainingthe axis thereof. The stub shaft 105, in this forni of inechanisni, has ournaled thereon a ineniber coinprising a gear 112 which takes the place oic the gear 10i ot the torn previously described and which with the rear 103. Formed integral with or lixed to th @fear 112 is an eccentric 11o preferably having; its ec centric tace spherical to permit a slight universal movement thereen of an eccentric strap 11e. The outer end oi this eccentric strap is piyoted at 115 to the outer end oi: the center ma. On rotation of the gear 112, therefore, it is evident that rocking Inoveinent is imparted to the center about the eivot 111 to nieve the Werl: toward and l'roni the f;rin :lingl wheel7 the ainount of such inotion dependine on the throw ot the eccentiin' t being` tric 118 and t f et this threeY dependent on the setting and size of the change gear 163. While shown the relicvine motion in'iparted only to the tailstoch center, it is regarded as Wit-hin the to ci inay be nu eit ier straight or spirali); tiuted taps.

interni to any conditions which t in practice when W rlnng on Grinder eU/icc mounting cooperative relation to the or carriage is a edge shaped to Meur ted in e head and tailstock sui'iport grindingy wir s grind the thi t the tap This Wheel niay be inount iy suitable inanner te eitect the d i i l l lts, siiown s f is arried by a shei't 11res l. 8,

casingv 1541 by Which ineens the anguiar pesition et the sha; 15) may be adjusted by a rotary adjusti ot the iortion 152 ufith relation to the driin.. llie grinding Wheel 155 is cai .d by 'the shaft 150 diametrically with relation to the portion nind entends through 156 therein best shown in Figures 8, 9, and 10. rEhe plate 152 inay be adjusted argularly, as above described and fixed in gosition relative to the casing by ineans of clamping; bolts 1e? passing thro ing;

the il te bridg the circular portion 153 and the casi This angular adjustment is 'for 'the jk et enabling he line et cuttii'ig action et Wheel to be adjusted in accordance Wi pitch oil Vthe tap thread. rEhe casi tornicd en tl e end oi? 160 .v inuy be nieu @ted in any suitable manner perinitting the Wheel a id tie work to be given qh the circular portion 153 and iich a relative feeding movement. ln the present embodiment this effected by forming the carriage as a slide movable on the base 1 at i' angles to the inovenient of the work iage 3 and toward and from the path of movenient thereof. By this construction the grinding wheel properly presented to the work and by sliding the carriage 100 feed and retraetive moti ons may be imparted thereto in proper time with a. traversing movement of the carriage 8 which supports the tap.

F or the purpose of driving the grinding wheel the rear end of this carriage 100 has fixed tlnfreon a cradle on which is pivoted, by a pintle 108, the axis of which is in alinement with the axis of the disk portion 158, a motor support 164 carrying thereon a motor 185. The drive pulley 166 of this motor is belt connected by a belt 167 through an opening 168 in the plate 152 with. a belt pulley 169 keyed to the shaft 150. 'lhe pivotal mounting of the motor is provided to permit its axis to be adjusted parallel to the axis of the shaft 150, or nearly parallel as necessary to secure proper driving effect on this shaft.

ln order to avoid the necessity of reversing the direction of rotation of uthe tap on a reverse direction of traverse, this reverse direction is made idle and for this purpose it is necessary to withdraw and so hold th grinding wheel while this traverse is taking place. For this purpose the following mechanism has been provided. Referring to Figures 4 and 8, the base 1 beneath the carriage 180 is provided with a bracket 180 having its up u' end formed as a sleeve 181. Slidable through this sleeve is a plunger 182 which is prevented from rotation relative to this sleeve by a lug i8 depending from one end thereof and e p rhin; between guide ribs 184 formed on the machine base 1. rlhis plunger 182 is hollow and one end is threaded through a portion of its length as shown at 185. 1n enga gement with the threads of this portion is a screw 186 formed on a shaft 187. rlhis shaft journaled in a lug 188 extending downwardly from the carriage 160 and is pre- Vvented from axial movement relative thereto f, by means of a thrust member 189, which may be formed either as a sleeve fixed to the shaft 187, or it may he made integral therewith, which bears on one side of the lug 188, and a gear 190 fixed to the shaft on the opposite end of the lug 188. T.'T-.ith this constructirm it is evident that movement imparted to the plunger 182 acts to move the slide 160 to impart feed and reti-active motions te the wheel, and also vthat the relative positions of the carriage 1GO and the plunger 182 may be adjusted by rotation of the shaft 182. hilovement of the plunger 182 is 'effected to withdraw the wheel from cutting engagement with the work by means of a cam member 195 (see Figures 5, 6, and 7) adjustably fixed to the periphery of the cam drum 7, above mentioned, which acts at certain times to impinge against a bell crank follower arm 196 (see Figures 4, 6, and 7 the outer end 197 of which (see Figure 4) engages in a notch 198 in the inner end of the plunger. The slide 160 is normally urged to the inward cutting position of the wheel by means of a tension spring 200 fixed at one end to a lug 201 depending from the slide 160 and at its opposite end to a portion of the bed 1. The forward limit of motion of the plunger is determined by means of a stop 202 formed as a pin seated within an upstanding wall member of the machine base.

As before stated the relative positions of the slide 160 and the plunger 182 may be adjusted by rotation of the shaft 185. For the purpose of effecting this rotation the sleeve portion 189 has keyed thereon a gear 20." which meshes with an elongated gear 208 fixed to or integral with a feed shaft 207 j ournaled in the machine base 1 and extending through the forward face thereof where it has fixed thereto a gear 208 and beyond this gear a hand wheel 209. Hand feeding may be effected by rotation of the hand wheel 209 and there is also a power feed mechanism which acts through the gear 208. This power feed mechanism is driven in proper time relation to the work t averse by means of mechanism shown more particularly in Figures 1, 2, 8, and 8. As shown in these figures a cam plate 220 is adjustably fixed to the outer face of the cam drinn 7 and is adapted to impinge at certain times on a follower roll 221 carried by an arm 222 fixed to a rock shaft Forwardly of the machine base this rock shaft carries a bell crank lever 224 to the upper end of which is pivoted a link 225 which extends downwardly and is pivoted at its lower end at 226 to the lower end of an arm 227 journaled on a stub shaft 228. The upper end of this arm 227 is normally urged to the right, as shown in Figure 1, by means of a spring 229 engaging at one end a pin 230 on the arm 227 and at the other end a pin 231 extendin g outwardly from the machine base. The upper end of this arm 227 has pivoted thereto a. gravity actuated pawl 285 adapted to engage in ratchet teeth 286 of a wheel 237 journaled on the stub shaft 228. Fixed to rotate with this wheel is a pinion 289 which meshes with the teeth of the gear 208 on the feed shaft. rocking motion imparted to the arm 227 it therefore evident that the feed shaft may be rotated to turn the screw shaft 186, above n'ientioned, to impart feed motion to the grinding wheel. rlhe ext-ent of feed motion at each actuation of arm 227 is adjustable, this being determined by a stop comprising a bolt 240 having a knurled head 241 and extending through a threaded boss 242 projecting from the front face of the base 1, the end of which bolt is engaged by y the lower arm 248 of the bel1 crank lever 224i.

Vz the Wheel 28 t lmit the total extent d by the amnnatio this purpose a pawl 1:1 or knock-oft' may be employed, shown this comprising an arm 25o ]ournaled on the stub shaft 228 d havinc fzclfotf cam portion 251 Whicn is adapted to move beneath a portion of the pani. "85 and lift it from engagement with the teeth rll 's arm may be adjustably positioned angularly v. i relation to the vheel and roi' this purpose is provided with a i,M having internal gear teeth cut therein, as shown at 252, with which may engage a pinrotatably by turning a lrnob 255 fixed thereto. A spri g-pressodMuneer-258 in a socket 2li/t in the ar @Of 1, ratchet teeth on th ltnob and acts Uo yieldingly hold the pinion in any angular position to which it nay be turned. is evident that turning` of this pinion changes the angular' setting of rin 250 relative to the wheel 287. rllhe plunger also pernnts tie amount of turning to be evicent to the operator Who may readily feci the movement of each ratchet tooth. lilith this construction, after sufficient feed .ioveinent has taken pia o to bring the release can?. 251 in engagement with the paWl the latter raised from engagement with the te 1th 286 and 'further movement of the arm of the cam becomes ineffective to impart feed movement to Wheel.

Trm'nf/ mechanism 1n order to VLreduce accurate Werl; it is necessary that the cutting faces of the grinding Wheel be trued. For this purpose novel truing mechanism has been provided which is also designed so that when the thraded faces of the tap have been ground to the proper size any further relative feeding motion between the tap and grinding Wheel will be me'l ective to cut deeper since a correspondingzj equal movement of the truing devices or toolsI is produced to remove the cuttino; faces of the Wheel at the saine rate as the feeding movement. @ne embodiment of the truing mechanism is shown in Figures 4, 8, and in which the devices are shown as carried on a slide 270 mounted in guides on 'the upper face of the slide 1G() and moving parallei to the direction of motion of this slide. The truing mechanism, therefore,

moves with the carriage 1GO and is also capable of being moved independently thereof. This is effected by means of a screw 271 formed on the end of a shaft 272, the threads engaging in a lug 278 depending from the slide 270. The shaft 272 is journaled in a bearing boss 274; upstanding from the rear end of the carriage 160 and is prevented from moving axially relatively thereto by an en- L Aw on or slee e fixed to or intetherewith bearing on one side of the e 274-, and a sleeve 276 journaled on this bearing on the opposite side of the The sleeve 276 has a flange 277 veen 7hieh is formed as a gear and meshes r. the teeth of gear 190. r1`he outer end of the sleeve 276 has a disk-shaped flange 278 thereon with vhioii engages frictionally a disk 279 keyed to the outer end of the shaft 272 and adapted to be clamped against the tiange 278 by means of a nut 280 threaded on the outer end of the shaft and engaging a b- Washer 281 impinging on the outer 2 fr handle 282 is also fixed -a of a. dish 279.

he disl; 279 by which it may be turned,when nut 280 has been loosened, to impart roation to the shaft 27 2 independent of rotaon imparted thereto through the gear 277. this means, When the nut 280 has been tightened, motion imparted to the. gear 190 through the feed shaft 207 also imparts a reed motion to the slide 270. The screws 271 and 186 of equal pitch so that feed motion vparted to the slide 160 when the nut 28() s clamper. in position imparts an additional movement of the slide 270 relative to the carriage 1GO in the same direction and of equal amount. The relative positions of the slide 270 and the carriage 160 with relation to the ivorl; may be changed by loosening the nut 280 and manipulating the handle 282.

before stated, the slide 270 carries the Y 'sm and for this purpose it is provided n ith a segmental-shaped casing portion 290 formed with spaced inner and outer concentric vertical Walls 291 and 292, end Walls and a cover plate 298 bridging the 'rop thereof. Centrally disposed through the walls 291 and 292 in the plane of the grind- 'no' Wheel is a. rock shaft 294 and between i ls 291 and 292 preventing` axial movement of this shaft, except as they may be relati rely adjusted, is a beveled gear 295 fixed thereto. At either side of this gear are fixed angularly disposed stub shafts 296, one only of which is shown in Figure 9, Which carry similar bevel gears 297 meshing with the gear rihese gears 297 in turn mesh with simii rears 298 fixed to shafts 299 Which y ed in the Walls 291 and 292 and to.vard opposite beveled side cutting i the grinding Wheel Where this Wheel eitends rearivardly of the plate 152. Each 'tts 2944 and 299 their inner ends uiiiivardly extending portions 800 in ,h are adjustably fined diamonds or other ble truing tools 801. These truing devices or tools are offset from the axes of their respectivo shafts, so that by rocking ting` faces of the i The tools are designed to act on the wheel at points dian'ietrically opposite to the action of the wheel on the work, and while the rocking motion imparted thereto to cause the tools Vto traverse the entire width of the cutting faces of the wheel brings them slightly out of this plane, the deviation therefrom is so slight as to be negligible. The rocking of" the tools to effect their truing strokes is effected by means of a cam element 319 adjustably fixed to the cam drum 7, before referred to, which acts on a cam roll 311 carried by a bent lever 312 (Figs. 2, (l and T) which passes out thro-ugh a side wall of the base 1 through an opening 313, where it has formed thereon a sleeve portion 31e journaled on a vertical pivot 315. lilxtending outwardly from the sleeve 31%1- is an arm 316 to the end of which is adjustably fixed an abutment screw 317 acting to limit the inward morement of the arm, this arm normally being held toward this limit of motion by a spring 318 engaging a perforated lug 319 thereon at one end and extending into the casing 1 and attached to a fixed point therein at the other end. The upper portion of the sleeve 314 has fixed thereto an upwardly inclined arm 320 having a horizontally perforated boss 321 at its upper end. Through this boss passes a pivot bolt 322 to which is pivoted by a vertical pin 323 a link 32-il (Figures 8 and 9). The inner end of this linlr is pivoted by a horizontal pivot bolt 325 to the upper end of an arm 326, the lower end of which is made fast to the outer end of the shaft 2911. It is therefore evident that as the cam drum rotates the arm 321 is rocked periodically and rocking motion imparted by the connections above described to the shaft 294 and through Athe bevel gears to the shafts 299, thus imparting truing motion to each of the truing devices.

A modified form of mechanism for imparting rocking motion to the truing device shafts and for adjusting the relative positions of the truing devices is shown in Figures 13 and 111. Referring to these figures the truing tools 301 are adjustably mounted in the ends of the centrally disposed rock shaft 29-1 journaled in the walls 291 and of the segmental-shaped portion of the slide 2T() and in shafts 330 positioned on opposite sides vof the central shaft and inclined relative thereto to act on the lateral cutting faces of the wheel in the same manner as described in connection with the first form. Each shaft 330, however, instead of being journaled directly in the wall 292 is ournaled in a bushing 331 seated in an opening therein and having a iange 332 at its inner end to prevent it from being removed outwardly through the opening in the wall 292. Through the rear end of each bushing 331 is threaded an adjusting screw 334i which bears at its inner end against the rear end of the corresponding shaft 330. By adjustment of these screws the endwise positions of the shafts 330 may be adjusted. A set screw 335 may be employed to loclr each adjusting screw 334 in adjusted position. Within the bushing 331 each shaft 330 is threaded as shown at 336, and screwed thereon is a collar rthis collar abuts against the rear end of a sleeve 333 which is slidably keyed to the shaft 330 and which is urged against the collar 33? by means of a coil spring 339 surrounding a portion of the sleeve 333 and bearing at one end against the inner face of the wall 291 and at the other end against a shoulder 3110 on the sleeve 333. By the pressure exerted on the collar 337 by this spring each shaft 330 is urged into engagement with the end of its adjusting screw 334. Each collar 333 has formed thereon a gear segment 341 which meshes with rack teeth 342 on a segment rack bar or face gear 343 which is mounted for limited sliding movement beneath the cover plate 293. rilhis segmental rack bar meshes with the gear segments 341 on each shaft 330 and also meshes with a similar segment, not shown, fixed to the rock shaft 294. By this construction it is evident that rocking motion of the roch shaft 294 may be t'ansmitted through the gear segment thereon to the segmental rack bar 343 and is imparted from this racl bar through the segmental bars 3st to the rock shafts 330 to impart truing movement to the truing devices 301 carried thereby. Adjustment of the collar 337 permit-s the position of the gear segment 341 axially of each roch shaft 330 to be adjusted in conformity to the axial adjustment of this rock shaft by means of the adjusting screw 331i. The rack bar 343 may be guided so as to be moved inan arcuate path by guide pins threaded in the cover plate 293 and projezting through slots in the rach bar or by guide slots cut in the transverse vertical walls connecting the walls 291 and 292.

Dm'oz'ng mechanism llO iwi

ing mechanism. These members are driven in the following manner. Referring more particularly to Figures 2 and 3, at 350 is shown an electric motor bolted to the rear vertical Wall of the machine hase l. riflie drive pulley ot this motor being; shown at 35i is belt-connected to a drive pulley carried hy a main poversliait rhis shait extends throueh a suitable hearing in the outer Wall oi hase l and in ivardly oi this hearing is ii ed thereto a pinion 354, as shoivn in Figures 5, and i'. This pinion meshes with a gear ournaled on a shalt and lined to rotate with the gear is a pinion This pinion meshes with a 358 jouriialed on a slia'lit @ne 'lace of the gear 358 carries clutch elements 360 and mating with these elements are clutch elements 361 ol a collar slidably keyed to the slia'lft 359. The collar @Gl is grooved for the reception oit jaws at the end oit an arm 536e (shown in dotted lines in Figure l), which is lined to a rochl shaft SGV. rlliis rock shaft extends th rnigh the iront Wall of the machine hed l and outivardly thereoil has liXed an actuating lever 3555 terminating` in handle 3G17. ly the actuation of this handle the rock shaft may he manipulated to clutch or uiichitch the gear 858 to the shait 359. Keyed to the shaft 359 is a gear 368 which meshes with a gear 3539 on a stub shaft 570. gear 369 meshes in the long gear 50, ahove mentioned, which is lined 'to the sliat't Gutvvardly .oi the fi-aine member l the shaft 359 has lined thereto a L; which meshes a gear 376 '5i Which extends through 'nais $378 Figure 7) in the machine hase l and carries on its opposite end a worin l il. 'this v-:orii'i ST9, as shown in Figures l, 2, and meshes with a vvorm Wheel SSO torn'ied in cgral With or attached to the lovfer portion o t 7. Through the mechanism just f le cam drum scrilied the cam drum 7 and 'the Work-rota' ng and relieving mechanism driven` t is drive he ing` controlled throug'l'i the clutch actuated hy manipulation of the handle lVith the machine constructed as above descriloed the cycle of operations may, if desired, he as follows. ii Working traverse of the tap may he eitected one direction past the grinding Wheel, the 'truil i that time being out oit operative o i and the tap being moved toward and om the ivheel in time With its rotation and i to properly torni the threaded te ere-oi1 With clearance from the cutting' eoV o; the

t tap at one side of each flute. At the end of this traverse a slight d veli in the trave. motion may occur and a ed -t imparted to the o'iinding vv k. eel and a motion ot' the same ampi `ude to the ii-ning' mecha iiism. The grinding vvheel and triiiiig mec ianism together are then retracto/c from cut .correct in shape to the extent to which position, and the return traverse of the Work carriage eected and if desired at a higher rate ot' speed than the Workingtraverse. During the idle traverse the truing devices may he caused to pass across the races of the grinding wheel to contact therewith or not depending on the relative setting` of the mechanism. At the end ot' the idle traverse the Wheel is again moved into its operative position which Will he further tovvard the ivorl: than on the previous Working traverse hy the amount oi' the feed motion given at the end of the p yevious Working;V traverse. 'lf he cycle ot' operations is then repeated until the Werl; is finished. The machine should he set, hoivever, so that prior to the automatic thifoiviiig` out of the feed hy the pawl lnioclt-oti', the truing,` devices shall have engaged effected a truiiig action on the grinding Wheel so that the final cutting' strokes shall lie made by the Wheel dressed to the proper form and fed to the required depth for the daiiieter ot the tap desired. ttention is called to the tact that after the completion ot' vWerl; on a single tap, should another tap he operated upon would not become operative on the ivheel and consequently the linished vuoi-l; would he in- Wheel had become inis'iiormed in the grind of the tap and would he over sized to the ei;- tent ol' the wear on the wheel. lt is therefore important that this pavil knock-oli mechanism should he set hach somewhat for each grindingl operation so that the tap operated upon will he reduced to accurate shape and size when the feed has automatically ceased.

Another cycle of operations possilile with this machine may he eiliected by ilirovidingi a lead cam 6 having a pair of spaced liiggli portions to effect tivo complete traverses ou each rotation of the cam. The tiuiiig' mechanism cam may then he positioned so as to give a single oscillation of each truine` device att-er the first operative traverse and to give a reverse motion to the truing de vices alter the second operative traverse, thus giving a single truiiig` stroke hetiveen each operative traverse of the ivork instead of tivo truinp,` strltes as in the previouslyY described cycle, thus germittiiie` the time loi' the return idle traverse to he shortened and so somewhat increase the speed of the machine. Other cycles of operation, of course. could he provided hy changing` the 'forms oil the cams on the cam drum 7 and adjusting them iariously angularly relative thereto.

lVhile as shown the machine is desi gned lor operating' on taps, it is evident that many oil the 'features of the invention are applicable to the making` oi reamers, hoos and other devices, such modifications as he found necessary or desirahle being made to adapt the machine to the particul surface desired. 

